As shown in FIG. 1, a conventional scroll compressor 100 generally includes a housing 110, a top cover 112 arranged at one end of the housing 110, a bottom cover 114 arranged at the other end of the housing 110, and a partition plate 116 arranged between the top cover 112 and the housing 110 for separating an inner space of the compressor into a high pressure side and a low pressure side. The high pressure side is formed between the partition plate 116 and the top cover 112, and the low pressure side is formed among the partition plate 116, the housing 110 and the bottom cover 114. An inlet connector (not shown) is arranged at the low pressure side for suctioning fluid, and an outlet connector 119 is arranged at the high pressure side for discharging the compressed fluid. A motor 120 including a stator 122 and a rotor 124 is arranged in the housing 110. A driving shaft 130 is provided in the rotor 124 to drive a compressing mechanism including a non-orbiting scroll 150 and an orbiting scroll 160. The orbiting scroll 160 includes an end plate 164, a hub 162 formed at one side of the end plate, and a spiral blade 166 formed at the other side of the end plate. The non-orbiting scroll 150 includes an end plate 154, a spiral blade 156 formed at one side of the end plate, and a discharge port 152 formed at a substantially central position of the end plate. The orbiting scroll 160 is supported at one side by a main bearing housing 140, and the driving shaft 130 is also supported at one end by the main bearing housing 140. An eccentric crankpin 132 is provided at one end of the driving shaft 130, and an unloading liner 142 is provided between the eccentric crankpin 132 and the hub 162 of the orbiting scroll 160. Being driven by the motor 140, the orbiting scroll 160 orbits relative to the non-orbiting scroll 150 (i.e., the central axis of the orbiting scroll 160 rotates about the central axis of the non-orbiting scroll 150, however, the orbiting scroll 160 itself cannot rotate about its central axis) to compress the fluid. The fluid compressed by the non-orbiting scroll 150 and the orbiting scroll 160 is discharged to the high pressure side via the discharge port 152. A one-way valve or a discharge valve 170 is provided at the discharge port 152 in order to prevent the fluid at the high pressure side from flowing back to the low pressure side via the discharge port 152 under certain circumstances.
FIG. 2 shows an exploded perspective view of a conventional discharge valve 170. As shown in FIG. 2, the discharge valve 170 includes a substantially annular valve seat 172 (a valve port 175 is provided in the valve seat 172), at least one valve flap 174 arranged at the valve seat 172 for opening or closing the valve port, a valve stop 176 for preventing the valve flap from being excessively deformed, and a pin 179 for fixing the above components together. The discharge valve 170 with the above construction is fixed in the hub 153 in the vicinity of the discharge port 152 of the non-orbiting scroll 150 (shown in FIG. 4) via a holder 178 (see FIG. 4). FIG. 3A shows the discharge valve 170 in a closed state, and FIG. 3B shows the discharge valve 170 in an opened state.
In the conventional discharge valve 170 shown in FIGS. 2 to 4, due to the specific position relationship of the valve seat 172, the valve stop 176 and the holder 178 relative to the discharge port 152 of the non-orbiting scroll 150, when the compressed fluid is discharged from the discharge port 152 to the high pressure side, the flowing direction of the fluid is turned by substantially 90 degrees each time at portions A, B, C and D shown in FIG. 4. An upper surface of the valve seat 172 is perpendicular to an axis direction of the discharge port 152 (or the valve port 175 in the valve seat 172). Thus, when the valve flap 174 opens, the fluid has to be turned by substantially 90 degrees (at position A). Next, since an axis direction of a flowing passage in the valve stop 176 is substantially parallel to the axis direction of the discharge port 152, the fluid flowing out of the valve flap 174 along substantially a horizontal direction has to be turned again by substantially 90 degrees (at position B). Finally, the fluid flowing out of the flowing passage of the valve stop 176 along substantially a vertical direction is directed by the holder 178 and tends to flow towards an area which has the smallest pressure. Hence, the fluid is then turned by substantially 90 degrees each time at substantially positions C and D. These turns significantly increase the flowing resistances of the fluid. Hence, a significant pressure drop is caused from the discharge port 152 to the high pressure side. This kind of pressure drop may result in a reduced efficiency and an increased energy consumption of the compressor.
Therefore, there is a need for a discharge valve which can effectively reduce the flowing resistance.